Relay system



May 6, 1924.

W. SCHOTTKY RELAY SYSTEM Filed Nov. 2, 1920 Patented Mayfi, 1924. f IUNITED STATES PATENT "oFFics.

WALTER SCHOTTKY, OF WUBZBURG, GERMAIIY, ASSIGNOB '10 SIEMENS-OCHUGKEB'I-WEBKE GFSELLSCHAIT MIT BESCHRANK'I'EB HAI'TUNG, OF SIEMENSS'IADT, NEAR31mm, GERMANY, A. CORPORATION OF GERMANY.

mar srs'rnu.

Application filed November 2, 1920. Serial l l'o. 421,898.

(emm mu m raovrsronsor an AM. or macs a, 1921, 41 sur. r.., ma.

To all whom it may concern:

Be beknown that I, WALTER ScHo rrKr,

a citizen of the German Empire, residing at Wurzburg, Germany, haveinvented certain new and useful Improvements in Relay Systems, for whichI have filed applications in wermany' July. 12, 1916, June 30,

. 1917, July 17,1918, and Aug. s, 1918; in-

telegraphy and the like. In the case of 'con-.

. nections of this gd, there are generally arranged in front the firstand to the rear of the last amplifier, and also intermediate the severalamplifiers, transformers-for the purpose a: transmitting the amplifiedalternating current only. Now, such a large number of transformerscannot in most cases be disposed so as to avoid mutual interference witheach other. 'Ifhese influ-- ences areartly due to the magnetic strayfields; besides such transformers are mutu-- ally interconnected by thecapacity of their relatively to each other and to the earth. By reasonof these two causes there are produced disturbances which makethemselves disagreeably perceptible either by loud noises, or by thesingmgor howling of the entire system. In the event of the necessi .ofsurrounding the transformers wi iron-jackets for the purpose ofprovidinga magnetic protection, the inherent considerabfloflfissessustained in such transformers are er increased to a large extent.

" It has already been proposed to substitute for the transformers acombination of achoking coil or ohmic resistance in the output circuitof one amplifier with a batto in the input. circuit of the succeedingamplifier, the said circuits being directlyconnected to each other andthe batte'ry serving to counterbalance the direct current in the out utcircuit of a the receding amplifier. uch an arranglement as, however,the disadvantage t a the regular of the connection depends greatly Ithas further been proposed to use in the output circuit of theamplifiersa choking coil and to connect this output circuit to the inputcircuit of the following amplifier over a capacity. Such an arrangementhas vantage that on account of the the disa choking coil it is"'tooselective for several purposes.

According to the'present. invention ohmic resistances are inserteddn theout ut and input circuits and the connection etween the output and inputcircuits is made over a capacity. The use of ohmic resistances offersthe distinct advantage that the connection produces for all frequenciesthe same amplifying efiect since in contradistinctionto choking coils,oscillatory circuits or transformers and similar expedients,

ohmic resistances are entirely independent of the frequencies. For thisreason a 'connection in which resistances are employed 1 will proveparticularly suitable for amphfy-- in%telephone currents pecialadvantages will furthermore re' sult in cases where it, is a question ofamplify-ing alternati' currents of low frequencies, say, of a ut' 50periods by second. In such a case, choking coils or transformersemployed for obtaining suiiicientllvl large impe ance values would uiresue a quantity of iron or copper win 5 ohmic resistances will be foundto 0- superior, insofar as sa in weight and material are concerned.'-inally attention is also directed, to the fact that ohmic,

resistances are referable for the reason that the em y no ma etic fields,' as

.compa with choking co' or similar e;-

dients which produce disturbances caused y feed-bac henomeua."

However, a so in the case of other installations operating with but onefrequency, such as wireless or similar signalling arrange- ,The ohmicresistances d,d, are lodged ments, and where this frequency is alteredfrom time to time, a connection of the character described, embodyingresistances, has certain advantages because, 'owing to the degree ofamplification being independent of,

the frequency, a special setting of the amplifying circuit to a maximumdegree'of amplification will not be required, whereby again thenecessity of adding further devices, requiring syntony with therequisite tuned elements of these circuits, such as antenna, resonancecircuit, etc. will be obviated.

Ohmic resistances will moreover be found especially suitable in caseswhere it is a question of faithfully reproducing signals, because oftheir non-selective roperties. It is essential in this case that teresistances be always suitably dimensioned. According to the presentimproved arrangement they are so chosen that the capacity and theresistances within the anode and the service circuit will form a systemthe damping period of which exceeds the duration of the si :11transmitted. In such case, resistances 0 an extremely high value mustbeemployed. They are considerably larger than those used in an ordinaryconnection. Thus, for example, in the case of an average transmittingspeed, there will be obtained for a damping period of one second, onemicrofarad for the condenser and one megohm for the ohmic resistance.

An embodiment of my present invention is shown in the accompanyingdrawing in which a connection of thermionic tubes by means of ohmicresistances and capacities is re resented in diagrammatic form.

n the drawing a connection for three" amplifier tubes E,--E isdisclosed. In the case shown these tubes are provided each with aspecial set of batteries B,-B The' individual amplifiers are connectedwith each other and with the receiving instrument T by a single lineonly while their second le is earthed. Within the single junction ineare arranged the condensers G -r43 including the plates weaves withinthe output circuits in the amplifiers -1), and filaments 71-7,respectively. heir value must be eriplial to that of the tube resistanceto ena e trans erred on to the grids Il ir By means of the ohmicresistances r,-1' the negative potential of the batteryappertainingthereto is connected to the auxiliary electrode or grid ofthe respective amplifier.

Of course the invention is not restricted to the exact connection of theconventional amplifier element shown, for instance'the individualbatteries, which may be grouped possible fluctuations of voltage to beand connected in any other suitable way known in the art.

I claim:- q a V 1. In a connection for alternating current or directcurrent impulse amplifiers, each having an input and anbutput circuitand a source of direct current ,containedin the output circuit, an ohmicresistance in the output circuitof each amplifier, a capacityin theconnecting line between the qutput circuit of one amplifier and theinput circuit of the succeeding amplifier and an ohmic resistanceinserted in the input circuit of each amplifier.

2. In a connection for alternating current direct current impulseamplifiers, each having an in ut and an output circuit and a source ofirect current contained in the output circuit, an ohmic resistance inthe output circuit of each amplifier, a capacity in the connecting linebetween the output circuit of one amplifier and the input circuitof thesucceeding amplifier /and an ohmic resista co inserted in the inputcircuit of each a lifier, the said ohmic resistances and capacities ofconnected output and input circuits being chosen to form a system, thedamping period of which exceeds the'duration of the signal to betransmitted.

In testimony whereof I afiix my signature.

WALTER soHoT'rKY.

